The present invention applies to the taxiing of an aircraft such as, particularly, a civil or military airplane, transporting passengers or goods (freight), or a drone (pilotless aircraft). More particularly, it relates to the generation of a trajectory on the ground, which is such that the aircraft can be manually or automatically guided along this trajectory on the airport domain. Furthermore, the method and system for aiding the piloting include, respectively, a method and a device generating such a trajectory.
Within the scope of the present invention, it is meant:                by taxiing, any type of possible running of an aircraft, such as the running on takeoff and landing runways, the taxiways, the turning-around areas, the waiting zones, the stop bars, the stop or stand positions, the maneuvering areas and the parking areas among others; and        by trajectory on the ground, the way to be followed by the aircraft on the airport domain, including particularly the takeoff and landing runways, the taxiways, the turn-around areas, the waiting zones, the stop bars, the stop or stand positions, the maneuvering areas and the parking areas.        
The path to be followed on the ground is generally given to the pilot, for instance through radio-communication means or through other ordinary means such as a digital data transmission link, by an air traffic controller or a ground controller, but it can also, in some cases, be freely chosen by the pilot.
The path is defined as an element succession on the airport domain, and indicates a way for reaching, from a point or region of the airport domain, another point or region of said domain.
Within the scope of the present invention, it is called by airport domain, any portion of the domain, referred or not as a designation, and identified as a distinct and bounded part of the domain. By element, it is particularly referred to a part or all the surfaces bounding the takeoff and landing runways, the runways, the guiding ways, the taxiway sections, the turn-around areas, the waiting zones, the stop bars, the stand positions, the maneuvering areas and the parking areas.
Within the present invention, furthermore, it is referred as:                a surface element, a polygon bounding and locating at least one part of an element surface (runway, taxiway, . . . ) of the airport domain; and        a polyline, a series of lines forming a guiding line.        
Furthermore, it is known that airport navigation systems mounted on-board airplanes enables to visualize the airport geometry, and for some of them (such as an OANS (“On board Airport Navigation System”) type system, so as to show the current position of the airplane on the airport map displayed on the piloting station. The airport map can be shown on navigation screens or on those of the world being opened according to the applications.
The airport maps are generated from on-board current databases. These databases are formed ordinarily from air images of the airport which are discriminated in different elements (runways, sections of taxiways, guiding lines, . . . ), each element being defined by a set of points and different attributes enabling the on-board system to draw the airport geometry as it is shown on paper maps (Jeppesen type) or scanned in the systems of the EFB (“Electronic Flight Bag”) type.
The on-board system will shall have to make do with reading databases, interpreting the information defining the different constitutive elements of the airport, and displaying them by connecting the points by straight lines so as to graphically give back either the surfaces or the guiding lines painted on these elements.
The format definition of these on-board databases has been normalized (standard ED-99B). This definition covers all the map displaying cases, but has not been planned to display trajectories. In particular, the geometry of each element of the airport is precisely and completely described therein, but there is no link between the different elements, so that it is not possible to directly identify, simply by reading the database, a way allowing to go from a given point of the airport to another point while respecting a succession of predefined elements.
In order to try and solve this difficulty, the document WO-2009/016135 describes a method for creating an additional layer, in addition to the current databases, which enables to connect the different elements to the database between them. However, this solution has some disadvantages. In particular, the connectivity layer is defined on the ground on the whole airport surface and is subjected to an additional database which is loaded in the airplane at the same time as the airport database ED-99B, which forces the airline to load a second database of an important size, thus causing an immobilization of the airplane more important than required for the loading of the single airport database.
Other solutions could be envisaged on the base of a new airport database format, which can be discussed within the scope of standardization activities, but may lead to major evolutions of the tools currently used by database providers and may need important investments. Furthermore, such standardization activities are always very long, and the availability of a new standard (ED-99C), taking into account the requirements of any connectivities required for the running trajectory direct generation, could take many years.
The present invention aims at remedying the above mentioned disadvantages. It relates to a method for aiding the piloting of an aircraft, in particular a transport airplane, running on the ground, which comprises a process for generating a taxiing trajectory of the aircraft on the airport domain.